Methods for washing and cleaning solid materials, in particular textiles, are widely known in the art. Moreover, suitable detergents and cleaning agents to carry out such methods are know wherein the function of the phosphates in binding calcium in complexes is taken over wholly or in part by finely divided, water-insoluble aluminum silicates capable of binding calcium (German OLS 24 12 837).
These are compounds of the general formula: EQU (Cat.sub.2/n O).sub.x .multidot.Me.sub.2 O.sub.3 .multidot.(SiO.sub.2)(I)
where Cat is an n-valent cation exchangeable with calcium, x is a number from 0.7 to 1.5, Me is aluminum and y is a number from 0.8 to 6, preferably from 1.3 to 4.
The preferred cation is sodium, though it may also be replaced by lithium, potassium, ammonium or magnesium.
The above defined compounds capable of binding calcium hereafter are termed "aluminum silicates" for the sake of simplicity. This applies especially to the preferred sodium aluminum silicates; all statements made relative to the latter concerning their use according to the invention, further all statements relative to their properties, apply corresponding to all of the above defined compounds.
The aluminum silicates that are especially well suited for use in detergents and cleaning agents are those that have a calcium binding capability of 50 to 200 mg CaO/g of the anhydrous aluminum silicate. As used herein the term "anhydrous aluminum silicate" is intended to mean that state of the aluminum silicate which is reached after drying at 800oC for 1 hour. During this drying, the surface water and bound water is virtually entirely removed.
When manufacturing detergents and cleaning agents containing in addition to their conventional components also the above defined aluminum silicates, it is preferable that the initial aluminum silicates should be moist, as for instance on account of the method of preparation thereof. In the process, the moist compounds are mixed with at least part of the remaining components of the detergent or cleaning agent to be produced. By means of conventional steps such as spray drying, the mixture is converted into the final detergent or cleaning agent, as for instance a free-flowing product.
Within the scope of the above outlined preparation of detergents and cleaning agents, the aluminum silicates are supplied, for example in the form of aqueous suspensions. In this regard it would be desirable if further improvements in the properties of the suspension could be achieved, for instance stability and pumpability of the aluminum silicates dispersed in the aqueous phase.
It is known to employ alkylphenolethylene adducts in the formation of suspensions of aluminum silicates. Illustratively, adducts with 6 to 7 moles of ethylene oxide are used (German OSL 26 15 698).
Increasing emphasis is placed on biological degradability of detergents on account of ecology and the environment. In addition to the primary degradation; i.e. the loss of surfactant properties, the secondary degradability, namely mineralization, is assuming increasing significance.
Both the primary and the secondary biodegradability depend on the linearity of the carbon chain, in other words, the biodegradability as a rule will be the poorer with increased branching of the carbon chain.
Because of their benzene ring and their branched nonyl residue, the nonylphenol ethoxylates used in the German OLS 32 09 631 are poorly biodegradable, there being a special danger that a metastable decomposition product be formed in the form of toxic nonylphenol. This is the reason that the German detergent industry has renounced using nonylphenol ethoxylates. Switzerland is expected to ban its use also.
The iso-tridecyl alcohol ethoxylates employed in the German OLS 34 44 311 concerns, as indicated by the name, branched-chain oxo-alcohols with a branching rate of at least 50%. Furthermore these are isomeric mixtures of undeterminable structure, frequently with all kinds of possible branchings such as methyl, ethyl, propyl, iso-propyl and others.
Accordingly a prejudice existed in the art that preferably only such branched surfactants were suitable for the zeolite A slurry stabilization.